This is a Divisional of application Ser. No. 15/146,207 filed May 4, 2016, now abandoned. The entire disclosures of the prior applications are hereby incorporated by reference herein their entirety.
Technical Field
The present invention relates to a device for producing a composite active material powder and a method for producing a composite active material powder.
Background Art
In the field of all-solid-state batteries, there is an attempt to improve the performance of all-solid-state batteries, focusing on an interface between the electrode active material and the solid electrolyte material.
Examples of conventional methods for coating the surfaces of active material-containing particles with a sulfide-based solid electrolyte, include gas phase methods such as pulsed laser deposition (hereinafter may be referred to as PLD). However, the PLD method is generally slow in film-forming rate, so that it is remarkably low in productivity and is not practical. Also in the PLD method, the target of the sulfide-based solid electrolyte is turned into a plasma by laser irradiation. At this time, the composition of the sulfide-based solid electrolyte may be changed and may not be maintained.
Examples of other methods for coating the surfaces of active material-containing particles with a sulfide-based solid electrolyte, include mixing/kneading methods using a medium such as planetary ball mill. However, in such mixing/kneading methods using the medium, mechanical damage is applied in collision with the medium and, as a result, the surfaces of the active material-containing particles may be damaged. Therefore, to avoid such mechanical damage, there is a demand for mixing/kneading methods using no medium.
For example, in Patent Literature 1, as a technique to solve the above problem, a method for obtaining a composite powder is disclosed, in which different kinds of powders are bound by applying a mechanical action, which contains compression and sheer forces, to a raw material powder, which is made from various kind of powders, using a powder treating device.
Patent Literature 1: Japanese Patent Application Laid-Open No. 2010-180099
However, the use of the conventional composite active material powder production device as disclosed in Patent Literature 1, is problematic in that the internal resistance of a battery using the thus-obtained composite active material powder is large.